1. Field of the Invention:
The present invention relates to golf balls. More particularly, the present invention relates to the improvement of dimples of golf balls.
2. Description of the Related Art:
Golf balls have numerous dimples on the surface thereof. The dimples disrupt the air flow around the golf ball during flight to cause turbulent flow separation. By causing the turbulent flow separation, separating points of the air from the golf ball shift backwards leading to the reduction of drag. The turbulent flow separation prolongs the gap between the separating point on the upper side and the separating point on the lower side of the golf ball, which results from the backspin, thereby enhancing the lift force that acts upon the golf ball. The reduction in drag and the elevation of the lift force are referred to as the “dimple effect”. Excellent dimples disturb the air flow more efficiently. Owing to the excellent dimples, great flight distance can be achieved.
In addition to the flight distance, aerodynamic symmetry is also important for the golf balls. Flight distance of the golf balls that are excellent in the aerodynamic symmetry is not dependent on the impact point. Golf players can easily let the golf ball drop to a target position. Aerodynamic symmetry is important also in view of conformity to the rules defined by the United States Golf Association.
In light of the flight distance and aerodynamic symmetry, various proposals on dimple pattern have been made. JP-A No. H4-109968 discloses a dimple pattern formed on the hemisphere comparted into 6 units. US 2004/157682 (JP-A No. 2004-243124) discloses a dimple pattern in which an octahedron is used for compartments in the pole vicinity region, and an icosahedron is used for compartments in the equator vicinity region.
A top concern to golf players for golf balls is the flight distance of the golf balls. In light of the flight performance, there is room for improvement of the dimple pattern. An object of the present invention it to provide a golf ball that is excellent in flight performance.